Biplot for Principal Components using ggplot2
ggbiplot(pcobj, choices = 1:2, scale = 1, pc.biplot = TRUE,
obs.scale = 1 - scale, var.scale = scale, groups = NULL,
ellipse = FALSE, ellipse.prob = 0.68, labels = NULL, labels.size = 3,
alpha = 1, var.axes = TRUE, circle = FALSE, circle.prob = 0.69,
varname.size = 3, varname.adjust = 1.5, varname.abbrev = FALSE)an object returned by prcomp() or princomp()
which PCs to plot
covariance biplot (scale = 1), form biplot (scale = 0). When scale = 1, the inner product between the variables approximates the covariance and the distance between the points approximates the Mahalanobis distance.
for compatibility with biplot.princomp()
scale factor to apply to observations
scale factor to apply to variables
optional factor variable indicating the groups that the observations belong to. If provided the points will be colored according to groups
draw a normal data ellipse for each group?
size of the ellipse in Normal probability
optional vector of labels for the observations
size of the text used for the labels
alpha transparency value for the points (0 = transparent, 1 = opaque)
draw arrows for the variables?
draw a correlation circle? (only applies when prcomp was called with scale = TRUE and when var.scale = 1)
size of the text for variable names
adjustment factor the placement of the variable names, >= 1 means farther from the arrow
whether or not to abbreviate the variable names
size of the ellipse in Normal probability
a ggplot2 plot